What values for email "delivery-status" exist?
Posted on 2009-04-27
I'm creating a C# console app that will get emails from an Exchange mailbox, check to see if they are 'bounce back' emails and if so filter them as either 'hard errors' (where the delivery-type action is 'failed') or 'soft errors' (where the action is 'delayed'). Any emails not caught by this (such as 'unsubscribe') are then forwarded to a distribution list so various employees in my company can read those emails and take manual action as required.
My question is: what other types of delivery-status are there? 'Failed' is an obvious one I will work with (by locating and removing their record in my database, which is used to create recipient lists), and 'Delayed' is an action I can simply ignore for the most part.
What other actions are there that could be caught prior to forwarding on emails that need human interaction? Is there a list somewhere? Obviously I tried Google first, and then searched here, but no joy.